The present invention relates to television distribution systems and, more particularly, to television signal distribution methods and apparatus for substituting one television channel for another at a viewer premises.
Marketing research techniques have been developed in which a substitute television signal in a substitute channel containing a commercial, the effectiveness of which is to be assessed, is substituted for a normal television signal in homes of selected test viewers, so that the effectiveness of the commercial can be evaluated. This allows the promotor of the service or product to assess the reaction of a small, demographically controlled panel of test viewers before the wide airing of a commercial which may prove ineffective.
Signal substitution systems have been developed which provide marketing research signal substitution for the testing of commercials. Such systems employ a frequency converter in the nature of a cable television (CATV) converter which frequency converts selected channels to a base frequency, such as channel 3. All television receivers connected to the frequency converter are then tuned to channel 3 and receive the same programming selected by the converter. One example of such a system is disclosed in U.S. Pat. No. 4,733,301 issued Mar. 22, 1988 to Wright. The Wright system includes a frequency converter control box which receives both normal and substitute signals in frequency separated channels. During periods of non-substitution, the control box converts a normal television signal of a viewer's choosing to the frequency of channel 3 and applies the resultant channel 3 signals to TV receivers tuned to channel 3. The viewer changes channels by controlling the control box to present other television signals on channel 3.
When marketing research channel substitution is to occur, the viewer channel selection is overridden without viewer knowledge and a selected substitute channel is converted to channel 3 by the frequency converter. The result of this type of channel substitution is that the frequency converter control box selects the only TV signal, be it normal or substitute, which is applied to all television receivers connected to the output of the converter. When viewers wish to watch different channels from those being watched on other television receivers of the system, separate frequency converter boxes are required for each television. Although many televisions are being produced which are capable of receiving CATV signals directly without the need for a cable converter box, such a converter box is necessary for all television receivers to which channel substitution may be applied.
Prior channel substitution arrangements have a number of drawbacks. For example, each television in a test viewer's household must have a convertor box with capability of viewer channel selection and market research channel substitution. Such convertors are generally provided by the market research company, which then becomes responsible for maintaining all the convertor boxes in test viewer households. Since the marketing research company has no control over cable television parameters such as the channels available and their frequency assignments, the market research company must keep in close contact with multiple cable television distributors and change the convertor boxes whenever needed for cable television system compatibility.
Today's television receivers are capable of directly receiving cable television signals without the use of convertors. This situation introduces further problems. Many owners of such televisions would prefer to operate without a signal convertor so that they may take advantage of the capabilities of their television, such as picture-in-picture. This leads to test viewer resistance and, at times, results in test viewer households in which not all televisions are capable of receiving substituted channels. For best marketing research results, however, it is desirable to have all televisions in a test viewer household to be subject to channel substitution.
A need exists for viewer premises equipment which simply and conveniently provides controlled television signal substitution without the need for a per-television convertor and otherwise leaves viewer channel selection to the viewer and/or the viewer's cable television distribution company.